Abstract: As for constant-pressure gas production, the conventional semi-log plot of the inverse of the dimensionless rate versus the dimensionless time must be modified to account for high-velocity flow effects. Especially when reservoir permeability is higher than 1 mD, the well test is affected by non-Darcy flow and formation damage. This paper presents a new gas well testing analysis method considering gas well producing at constant pressure in infinite gas reservoir accounting for high velocity non-Darcy flow effects in vicinity of the well bore. This method is simple and direct and doesn't need type-curve matching or data regression. Case study shows that single constant pressure test can allow to precisely determine permeability, non-Darcy flow factor and skin factor of gas reservoir in gas well that constant-pressure well testing can be applied.

Key words: high velocity, non-Darcy flow, gas well, well testing